Starfish (Rifters, #1) by Peter Watts

A big international corporation has evolved a facility along the Juan de Fuca Ridge at the lowest of the Pacific Ocean to take advantage of geothermal power. They ship a bio-engineered team--human beings who have been altered to resist the stressand breathe the seawater--down to live and paintings on this bizarre, fertile undersea darkness.

unfortunately the best people suitable for long-term employment in those experimental power stations are loopy, some of them in unsightly ways. How many of them can continue to exist, or might be allowed to survive, at the same time a as worldwide disaster tactics from below?